Resistors with heat sinks find use in many applications where electrical current is required to be diverted from an electrical system for some purpose, and one important application is in a power transmission system wherein the resistor serves as a fault current limiter.
A fault current limiter must perform three important tasks in order to successfully accomplish its primary purpose of reducing the duty not only on the circuit breakers but also on the transformers, bus sections and all other equipment in a power system. First of all, it must reduce the first (or major) cycle peak current produced by a fully symetrical fault. Second, it must limit subsequent cycles of current after the initial peak and before the breaker opens to remove the fault. And third, it must absorb the heat generated when the fault current is diverted to the limiter.
In a paper prepared by Thomas H. Dodds and Narayan S. Rau, entitled "Current Commutation To A Resister As A Fault Current Limiter", background material on fault current limiters is outlined. A copy of this paper accompanies this application.
My invention provides an effective resistor with heat sink which is ideally suited for use as a fault current limiter in a power system. The construction may be produced at a relatively low cost, and comprises a tube formed of a metal having current resistive properties, and a material preferably highly compacted within the tube, the material having a high specific heat and being non-conducting.